The utility counselor's office says Duke's seven-year plan includes spending not allowed in a rate-increase request, including radio system replacements, vegetation removal projects and a proposed $3 million energy learning center. It also faults Duke for not providing as much detail as Northern Indiana Public Service Co. and Vectren Corp. when they sought approval for similar projects.

"The information we found in Duke Energy's filings does not meet the statute's requirements, while also falling short of the standards established in previous cases involving the approval of other utilities' plans," consumer counselor David Stippler said.

Duke spokeswoman Angeline Protogere said the North Carolina-based company has provided hundreds of pages of documentation about its plans and has responded to about 500 information requests from the consumer counselor and others.

"Our electric grid is aging and many components need to be updated and replaced," she said. "This plan is about modernizing our electric grid and bringing our system into the 21st century."

If the Indiana Utility Regulatory Commission approves the plan, Duke says its roughly 800,000 Indiana customers would see rate increases averaging about 1 percent a year between 2016 and 2022.

Duke's upgrade also would include installing new, advanced utility meters the company said would mean fewer and shorter electrical outages for its customers.